Shen Tai lives among the dead, and buries their bones by day while their ghosts cry at night. He is alone in the farthest western reaches of the sprawling nation of Kitai, on the site of an old battlefield. And he has been doing this work that no one else will do for two years, to honor the memory of his father, a prominent general. The battlefield and its ghosts are frightening enough to keep even the hardiest warriors from lingering after dark. But Tai takes it all in stride, all part of his self-appointed duty. A man can get used to anything.

And now, two events will occur that will not only alter Tai's life forever, but shape Kitai's entire future. The first is a message brought by a captain of the Taguran army, Kitai's neighboring country, with whom the empire has had a shaky history bouncing from trade to open war and back again. As Tai is burying the remains of both his own side and the Tagurans', both sides respect him and bring him provisions. But this message is something else entirely. Tai learns that a Kitai princess, married off to a Taguran prince, has made him a gift of 250 horses from the distant western nation of Sardia, where they know how to breed their horses. Given that a man who owns one of these powerful steeds would be considered fabulously wealthy, and as few as ten would be a gift worthy of the Son of Heaven himself, then 250 is simply beyond belief. If you happened to catch the news reports a while back about those homeless brothers in Hungary, literally living in a cave, who learned that a relative had died and willed them a fortune of over $6 billion, you begin to get an idea of how monumental this is.

It's so monumental, Tai's first thought is that he'll be the target of every assassin within a thousand miles. And sure enough, in a matter of hours, one turns up. An old schoolmate of Tai's arrives from the capital, Xinan. But before he can deliver his message, his guard, dressed in the garb of the Kanlin warriors (an apolitical monastic sect that trains fighters), turns out to be an imposter, kills the friend, and is only prevented from killing Tai by some helpful intervention. Burying all those bodies has earned some dividends. Tai has no choice now but to return to Xinan and decide how to collect and dispense with the horses. He will learn who tried to kill him (and no, it had nothing to do with the horses, as this person could not have known about them yet). He will discover the complexities of internal imperial court politics, in particular a rivalry between Wen Zhou, the rash and arrogant First Minister, and Roshan, a blustery and repellant military governer from the eastern provinces, that will have consequences. And he will discover that the horses are, ironically, all that's keeping him alive. The princess has specified that they are to be collected by Tai and no one else. Neither Zhou nor Roshan dare lay a hand on him unless they wish to deprive the empire of 250 pearls beyond price.

Under Heaven is, as you might have guessed, Kay's return to familiar territory after the contempo departure of 2007's Ysabel. Once again, an imaginary nation stands in for a real one, in this case, Tang Dynasty China. Kay has taken criticism for this, but I've never found it an artistically illegitimate thing to do myself. In an introductory letter to this book, he defends the practice as much as it needs: "I don't want to hitchhike a ride on the celebrity of a famous person.... Using the fantastic as a prism for the past, done properly, means a tale is universalized in powerful ways."

How is Under Heaven universalized? One way is in its portrayal of the personalization of politics, and how self-absorbed, arrogant men prioritize short-term desires over long-term needs, often to disastrous effect. Wen Zhou makes knee-jerk decisions based, not on careful consideration of what might be best for the empire as a whole, but what he thinks is best for him, right away, and he rationalizes his mistakes later. As I write this, I'm living in a politically splintered America in which politicians battle each other over petty differences in partisan ideology, rather than come together to fix real problems plaguing regular folks. And yet it's us regular folks who will pay for those politicians' idiocies, probably for the rest of our lives.

What a lush and expansive world Kay has created here. What textures and nuances are called up by his prose. Under Heaven is a magisterial work, the rare kind of story that absorbs you completely into itself. Written with Kay's signature sense of awe towards the grandeur of civilization and the forces that shape it and the lives of those with roles, large or small, to play in the drama of history, this is an unforgettable and essential epic from one of the field's titans.

There are books you encounter that present you with worlds you never wish to leave. This is one of those books. World-building has by now become a benchmark for how successfully a fantasy novel has done its work, but Kay was a master at it all along. Some people have this curious idea that there is "literature," and then there is the stuff you read that's actually entertainment. I'd suggest those people have an impoverished experience of reading, perhaps influenced by too many tedious school assignments. Great literature is that which provides the greatest entertainment, because it not only lights up your brain's pleasure centers, but the rest of the brain as well. Under Heaven is literary and supremely entertaining, and it may be Kay's very best.

Consider how skillfully Kay introduces themes that other writers might have treated didactically. A profound subtext to the story is the way in which women influence not only the acts of men but the course of nations. This is hardly a new or even deep observation, but Kay's handling of it adds a human dimension that makes you look at the whole notion from a fresh perspective. Whenever one of Kay's women becomes a viewpoint character — and there are so many incredible ones here — he shifts to present-tense voice. Ordinarily I'd peg this as an annoying stylistic indulgence (because that's just what present-tense voice is almost all the time it's used), except it's evident what Kay's doing here is showing us just how much more the women of Kitai have a stake in unfolding events. These women cannot wield power openly, and so must exercise what they can with a cunning that must often operate undetected right under the very noses of their men. And sometimes their power can be as great as any emperor's.

What would be simplistic from a lesser writer becomes, in Kay's hands, a sobering depiction of just how well these women realize the illusory nature of whatever security they have. In a culture where even a princess is nothing more than a piece of booty to be traded, with no say in how her very person is commodified, then women had better learn cunning and learn it damn well. Sometimes they learn too well. We never learn why this distant princess offered the horses to Tai rather than directly to the emperor himself, but we do know the results would have been very different. She has, on a whim, decided the fate of 40 million people.

Reading over the above, I find I've focused on aspects of this story I wasn't aware I was going to discuss when I started. In part, that's why I enjoy reviewing, the way thinking about stories continually reveals things about them long after reading. I also find I've left so much out, only scratched this novel's surface. I could go on about specific memorable characters, powerful scenes in which Kay gets more suspense from people in a room talking than many writers manage to squeeze out of full-blown battles. I'm tempted to ramble about the many genuinely haunting moments, like Tai's experience with shamanism in the far north, or his sister's discovery of wall paintings of horses in a remote cave. But these are moments you need to discover for yourselves. Five-star reviews like this one are harder to write than you might think, not only because so few books (at least by my standards) rate this highly, but because when they do, the trick becomes not only communicating my own pleasure at the experience but getting my readers to want that experience just as eagerly. And you don't do that by piling on the gushing hyperbole in Amazon fashion. You do that by being willing to say as little as possible when you want to say so much. So this is where I stop, with an effort, and sign off simply with, dear readers, I give you Under Heaven. I envy you.